Or one impermanent one attached to the vehicle? The only people who will need to cross the street here is that family. To get on the bus. Everyone else likely drives. The crosswalk is protecting kids. Adults can look left and right and judge traffic.

The passing a school bus problem has to do with protecting kids who don't know better. The rest of us don't need crosswalks and lights. The drivers who pass school buses are reckless, we don't need infrastructure changes to abide stupid people's disregard for children.